My Midnite Error Messages

[casaneil]

This recurring error message on My Midnite has been around since my install of 2 Classic 150's, 12 months ago.
Is this a problem or simply an 'error message' I should ignore?

Attached picture is attempting to describe the displays.

Using My Midnite with 2 x Classics, the Master ( Boss ) is always 1.5v on PV input at night.

But the secondary Classic ( Slave ) shows 0v or 0.1v at night.

Both Classics show error at sundown as 'Input is lower than output voltage'. Normal? We should all get this message I guess?
But second Classic always shows a 2nd error as 'input less than 1.0 Volt'.

My question is does a voltage of 0.0v or 0.1v indicate a system error. Like a panel diode not working? The second Classic ( Slave) is the lazy one in the pair and is a series/parellel PV array of mixed panels. The Primary Classic ( Boss ) has 6 x 200w in parallel.

Any comments please. Or do I stop pondering Error messages on My Midnite?